ML110550743
| ML110550743 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/2011 |
| From: | Bayssie M NRC/RES/DE/RGDB |
| To: | |
| Bayssie Mekonen/RES 251-7489 | |
| Shared Package | |
| ML110540127 | List: |
| References | |
| DG-1196 RG-1.107, Rev. 2 | |
| Download: ML110550743 (2) | |
Text
REGULATORY ANALYSIS QUALIFICATION FOR CEMENT GROUTING FOR PRESTRESSING TENDONS IN CONTAINMENT STRUCTURES (Proposed Revision 2 of Regulatory Guide 1.107, dated February 1977)
Statement of the Problem The U.S. Nuclear Regulatory Commission (NRC) issued Regulatory Guide (RG) 1.107, Qualification for Cement Grouting for Prestressing Tendons in Containment Structures, Revision 1, in February 1977, to describe quality standards that the NRC staff (staff) considered acceptable for the use of portland cement grout as the corrosion inhibitor for prestressing tendons in prestressed concrete containment. The staff is revising the existing RG: (1) to ensure consistency with other related RGs (e.g.,
RG 1.90, Inservice Inspection of Prestressed Concrete Containment Structures with Grouted Tendons and RG 1.136, Design Limits, Loading Combinations, Materials, Construction, and Testing of Concrete Containments), (2) to update the references in this RG that form the technical bases for staff regulatory positions, (3) to update the guidance to reflect recent revisions of the relevant American Society of Mechanical Engineers Boiler and Pressure Vessel code,Section III, Division 2, or ACI Standard 359, which is referred to as ASME Code in RG 1.107. Previously, the staff took some exceptions to the prior version of the ASME Code. The staff noted those exceptions in Revision 1 of RG 1.107. Later, ASME included those exceptions in the revised and newer ASME Code. Therefore, a revision to this RG is necessary to include the updated information in the new ASME Code.
Objective The objective of this regulatory action is to update the NRCs guidance on the use of portland cement grout as the corrosion inhibitor for prestressing tendons in prestressed concrete containment. This update will,in turn, give applicants and licensees the opportunity to take advantage of the revised ASME Code requirements and current staff positions. Updating the NRCs guidance in this area should lead to increased regulatory effectiveness.
Alternative Approaches The NRC staff considered the following alternative approaches:
Do not revise RG 1.107.
Update RG 1.107.
Alternative 1: Do Not Revise Regulatory Guide 1.107 Under this alternative, the NRC would not revise this guidance and would retain the current guidance. If the NRC does not take action, there would not be any changes in costs or benefit to the public, licensees, or the NRC. However, the no-action alternative would not address identified concerns with the current version of the RG. The NRC would continue to review each application on a case-by-case basis. This alternative provides a baseline condition from which any other alternatives will be assessed.
Alternative 2: Update Regulatory Guide 1.107
Under this alternative, the NRC would revise RG 1.107 to reflect the revised ASME Code requirements and current staff positions. One benefit of this action would be that the licensees and the staff would use the latest ASME Code requirements and current staff positions in evaluations. Therefore, the revised RG 1.107 would improve regulatory effectiveness while maintaining and enhancing safety.
The impact to the NRC would be the costs associated with preparing and issuing the revised RG.
The impact to the public would be the voluntary costs associated with reviewing and providing comments to the NRC during the public comment period. The value to the NRC staff and its applicants would be the benefits associated with enhanced efficiency and effectiveness in using an up-to-date common guidance document as the technical basis for license applications and other interactions between the NRC and its regulated entities.
Conclusion Based on this regulatory analysis, the NRC staff recommends a revision of RG 1.107. The staff concludes that the proposed action would improve regulatory effectiveness, increase efficiency, and maintain and enhance safety.
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